#pert {
  height: 600px;
  width: 100%;
  border: 1px solid lightgray;
  margin-bottom: 1em;
}

.container {
  padding-top: 4em;
}

#ta {
  margin: 1em 0 1em 0;
}

#tab {
  max-width: 40em;
  margin: 0 auto 0 auto;
}